1. Field of the Invention
The present invention relates to a weather strip to be mounted on a window of an automobile.
2. Description of the Prior Art
In an automobile shown in FIG. 1, a weather strip is mounted along an opening edge of a quarter window 1, and a peripheral edge of a hinged window glass is pressed against the weather strip of the quarter window 1.
FIG. 5 illustrates the conventional weather strip W to be mounted along an opening of the quarter window 1. The weather strip W is provided with a base portion 2 of a letter U-shaped cross-section and a seal portion 3 of a dogleg-shaped cross-section, which projects from the base portion 2. The weather strip W having the above-described structure is mounted on a flange 4 formed along an opening of the quarter window by forcibly inserting the flange 4 between retaining lips 21 of the base portion 2. The upper half of the dogleg-shaped seal portion 3 is made of sponge rubber. When the quarter window 1 is closed, the window glass 5 is pressed against the upper portion of the seal portion 3.
The fitting condition of the window glass to the quarter window is inevitably lacking in positional uniformity, and accordingly, the position (height) of the closed window glass is also lacking in positional uniformity.
In FIG. 4, the line C shows the relation between the height of the closed window glass and the pressing load of the window glass to the weather strip in the case of the conventional weather strip shown in FIG. 5.
When the window glass 5 is pressed to the dogleg-shaped portion 3, the pressing load is rapidly increased. As the window glass 5 is pressed further against the seal portion 3, namely the position of the glass surface of the closed window glass 5 is lowered, the seal portion 3 is bent at its curved point so that the pressing load is temporally decreased. And, as the weather strip is more pressed, the pressing load is increased again so that the seal portion 3 is bottomed on the side surface of the base portion 2.
FIG. 6 illustrates another conventional weather strip. The seal portion 3 is composed of a pair of dogleg-shaped portions 31a and 31b, which define a hollow portion 31 of a nearly lozenge-shaped cross-section, and a lip portion 32 extending from the top of the hollow portion 31 along a production of the upper half portion of the dogleg-shaped portion 31a.
In FIG. 4, the line D shows the change of the pressing load in this other conventional weather strip. In this weather strip, both dogleg-shaped portions 31a and 31b are bent simultaneously while being supported by each other. Therefore, the pressing load is greatly increased as the position of the window glass is lowered when the window glass is closed. In this weather strip, the temporary decrease of the pressing load which is encountered in the conventional weather strip shown in FIG. 5 (which is described above in relation to line C of FIG. 4) is not observed.
As described above, in the conventional weather strip, pressing load is greatly changed with the height of the window glass in the closing state.
Therefore, the conventional weather strip has a problem that when the closed position of the window glass is high, the seal force thereof becomes too small, and when the closed position of the window glass is low, the closing force thereof becomes too large.
In order to overcome this problem, it has been demanded to provide a weather strip to which a uniform pressing load is applied regardless of the change of the height of the closed window glass.